Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
  • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
  • H03B5/18—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance
  • H03B5/1805—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a coaxial resonator
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
  • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
  • H03B5/18—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance
  • H03B5/1841—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a strip line resonator
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
  • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
  • H03B5/20—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising resistance and either capacitance or inductance, e.g. phase-shift oscillator
  • H03B5/24—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising resistance and either capacitance or inductance, e.g. phase-shift oscillator active element in amplifier being semiconductor device

Definitions

• the present application relates to an oscillator with ohmic adjustable oscillation frequency.
• Oscillators are circuits for generating high-frequency vibrations.
• the core of an oscillator is an active device with a non-linear characteristic, such as a transistor or a diode.
• the oscillation frequency f of the oscillator is specified via a resonant circuit and its effective capacitance C and inductance L:
• the resonant circuit which can also be referred to as a resonator, can be realized with all frequency-selective components whose behavior can be described by an equivalent circuit of capacitance and inductance. Examples of these are discrete LC resonant circuits, dielectric resonators, cavity resonators or line resonators.
• oscillators In addition to fixed-frequency oscillators with only one oscillation frequency, there are still oscillators that can be changed in their oscillation frequency.
• the oscillation frequency can be varied by modifying the frequency-determining components of the resonant circuit mechanically or electrically. Mechanically modifiable components are eliminated in many applications where a fast frequency change is important.
• voltage controlled components are used in the oscillator. If voltage-controlled components are used in oscillators, this is referred to as voltage-controlled oscillators or VCOs (voltage-controlled oscillators).
• VCOs voltage-controlled oscillators
• VCOs voltage-controlled oscillators
• a general problem of monolithic integrated circuits is the dependence on a particular technology and its transistor architecture. For example, transistors for the millimeter-wave range are optimized for speed, which, however, does not allow the development of varactor diodes with optimum properties.
• monolithically integrated VCOs operating with varactor diodes often have a bandwidth of 5 to 8%, based on the average oscillation frequency. A higher bandwidth of, for example, more than 10% is associated with monolithically integrated varactor diodes with increased complexity and effort.
• the object of the present invention is to provide an oscillator with adjustable oscillation frequency, which allows high tuning bandwidths.
• Embodiments of the invention provide an oscillator with adjustable oscillation frequency, having the following features:
• a resonant circuit coupled to the terminal of the active device that exhibits the negative input resistance; and an element with adjustable ohmic resistance, by which the oscillation frequency of the oscillator is adjustable.
• the element with adjustable ohmic resistance can be used to vary the impedance of the resonant circuit and / or the impedance of a circuit structure with which the active element is connected to produce the negative input resistance.
• the effective length of a resonator line forming the resonant circuit can be adjusted to thereby adjust the resonant frequency of the oscillator.
• the element with adjustable ohmic resistance can be a transistor whose ohmic resistance can be adjusted via its control voltage.
• the oscillation frequency of the oscillator can be infinitely adjustable.
• Embodiments of the present invention allow for higher tuning bandwidths of an oscillator with adjustable oscillation frequency than can be achieved with conventional methods.
• the present invention is therefore of particular interest for monolithically integrated VCOs in the millimeter and sub-millimeter wave range from 30 GHz, in which a large tuning bandwidth is required.
• the inventive concept advantageously allows integration of oscillators with existing transmission / reception circuits and radar circuits on a chip. This can reduce the cost of construction and complete systems can be implemented smaller, lighter and more energy-efficient, which in turn can reduce the price.
• Embodiments of the invention thus provide voltage-controlled oscillators (VCOs) which are used as frequency-sensitive oscillators.
• tuning component use an ohmically tunable element or a voltage-controlled resistor.
• a transistor is used in parallel connection as the frequency-determining component.
• the element is connected to an adjustable ohmic resistance to change the effective electrical length or the impedance of a high-frequency line by changing the ohmic resistance of the same.
• an element with adjustable ohmic resistance can be used in any supply line of the transistor in order to influence the behavior of the transistor in such a way that the resonant frequency of the oscillator changes due to a change in the ohmic resistance.
• the oscillator may have only two discrete oscillation frequencies by the element with adjustable resistance between two extreme values is switchable. As a result of this switching, in embodiments between two extreme values of the adjustable electrical length or impedance, a high-frequency line can be switched over.
• Fig. 1 shows a first embodiment of an oscillator according to the invention
• Fig. 3 shows a third embodiment of an oscillator according to the invention.
• the oscillator comprises an active element in the form of a field effect transistor 10.
• the source terminal S of the field effect transistor Sistor 10 is connected via an element 12 for generating an instability with a reference potential, such as ground.
• the drain terminal D of the field effect transistor 10 is connected via an impedance matching network 14 to an output 16 of the oscillator.
• the instability inducing element 12 is designed to provide a negative input resistance at a gate terminal G of the field effect transistor 10.
• a line resonator Connected to the gate terminal G of the field effect transistor 10 is a line resonator having resonator line sections 18a and 18b.
• the line resonator represents a resonant circuit coupled to the gate terminal G.
• Line resonators can be implemented by short-circuited or open high-frequency lines, at the end of which high-frequency energy is reflected, so that a standing wave is formed.
• the resonant frequency of the oscillator is dependent on the length of the resonator.
• a long line causes a lower and a short line a high oscillation frequency.
• the line resonator or the resonator line sections can be implemented as short-circuited or open high-frequency lines.
• the oscillator also has another field effect transistor 20, which represents an element with adjustable ohmic impedance. More specifically, the resistance between the drain terminal and the source terminal of the transistor 20 is adjustable via a control terminal 22 by varying the voltage at the gate terminal G of the transistor 20.
• the ohmic variable element formed by the transistor 20 is between a tap 24 between the Resonator effete 18a and 18b and a reference potential, such as ground, connected.
• This element 22 thus represents a transistor in parallel, a so-called shunt transistor.
• the transistor 20 allows, depending on a control voltage at the control terminal 22, a variable current flow from the tap 24 against the reference potential. Thereby, the effective length and impedance of the line resonator, which is connected to the gate of the transistor 10, via the control voltage of the transistor 20 can be changed.
• the signal conductor of the resonator line is short-circuited at the location of tap 24 and the reduced resonator length of resonator line section 18a is effective.
• the entire length of the resonator line that is, the combined length of the resonator line sections 18a and 18b is effective when the transistor 20 is in the open state.
• the oscillator in FIG. 1 can be supplied, for example, with power via the matching network 14, wherein an oscillator output signal with an oscillating frequency is generated at the output 16.
• a power supply can be implemented, for example, by connecting the drain terminal of the field effect transistor 10 to a supply voltage potential via a choke coil.
• the oscillation frequency of the output signal is adjustable via a change in the control voltage of the transistor 20. For example, it can be switched between two oscillation frequencies by the transistor 20 is turned on or off. Alternatively, the oscillation frequency can be fine-tuned by controlling the resistance of the transistor to corresponding intermediate values.
• FIG. 2 shows an alternative embodiment in which the transistor 20 is not connected in parallel as a transistor is connected, but is connected in series between the two resonator line sections 18a and 18b.
• the effective length or impedance of the resonator line and thus the oscillation frequency can be set.
• the impedance of the transistor is in turn variable between an open state and a conductive state. In the open state of the transistor 20, only the length of the resonator line section 18a is effective, while in the conducting state, the length of both resonator line sections 18a and 18b is effective.
• the oscillation frequency of the oscillator signal at the output 16 can be adjusted.
• the element with adjustable ohmic resistance is provided to vary the impedance of the resonant circuit of the oscillator.
• 3 shows an alternative embodiment in which an element with adjustable ohmic resistance, which in turn is formed by a transistor 20, is provided to the impedance of the circuit structure, which is responsible for generating the negative input resistance of the active element 10 to vary. This also allows the oscillation frequency of the oscillator signal to be set at the output 16.
• a line resonator 18 is connected to the gate terminal of the active element 10.
• the drain terminal D is in turn connected via the matching network 14 to the output 16.
• the source terminal is connected to a reference potential, such as ground, via a radio frequency line having line sections 12a and 12b.
• the element with adjustable ohmic resistance 20 is between a tap 30 between the line sections 12a and 12b and a reference potential, such as ground, connected.
• a reference potential such as ground
• line sections 18a, 18b and 12a and 12b may be formed by separate high-frequency lines or by a single high-frequency line having a suitable tap at a suitable location, for example in the center.
• the resonator lines or resonator line sections may be formed for example by microstrip lines or coplanar lines.
• the resonant circuit may also be implemented by discrete capacitive and inductive elements. Also in such a case, one or more elements with adjustable ohmic resistance, such as transistors, may be used to vary the impedance of the resonant circuit to thereby adjust the oscillating frequency of the oscillator signal.
• transistor switches could be used to switch capacitances or inductances into and out of a resonant circuit, thus varying the impedance of the resonant circuit.
• elements with adjustable ohmic resistance can be provided by which both the impedance of the resonant circuit and the impedance of the switching structure provided for generating the negative input resistance can be varied.
• the element with adjustable ohmic resistance is formed by a transistor.
• any ohmic variable element may be used, for example a diode or, in general, a voltage-dependent resistor.
• the above embodiments have been described with reference to field effect transistors. It will be apparent to those skilled in the art that bipolar transistors may be used instead of field effect transistors, in which case the source, drain and gate terminals are to be respectively replaced by the emitter, collector and base terminals.
• the oscillation circuit is connected to the control terminal (gate terminal or base terminal) of the transistor.
• the resonant circuit may be connected to any one of the transistors (dram terminal or collector terminal or emitter terminal) of the transistor having a negative input resistance. as long as the other connections are connected in such a way that a swingable system results.
• Implementations for the matching network 14, for example, to accommodate 50 ohm line matching and to provide power to the oscillator, will be apparent to those skilled in the art and need not be further explained herein.
• the theory of oscillators in which an active element on a port connected to a resonator provides a negative resistance is known to those skilled in the art.
• Suitable circuitry of an active element such as a field effect transistor or a bipolar transistor, with an element for generating an instability, such as an inductance, a capacitance, and / or a high frequency line, to provide such negative resistance will be apparent to those skilled in the art also no further explanation.
• an active element such as a field effect transistor or a bipolar transistor
• an element for generating an instability such as an inductance, a capacitance, and / or a high frequency line
• Embodiments of the present invention thus provide a novel approach to varying the frequency of oscillation of a VCO, whereby higher through-voice bandwidths can be realized than with conventional methods. Furthermore, the present invention makes possible an excellent integration possibility with existing circuit concepts, for example transmit / receive circuits and radar circuits on a chip, so that complete systems can be implemented smaller, lighter and more energy-efficient with little effort.

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• Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)

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• 2009
  • 2009-02-10 DE DE102009008225A patent/DE102009008225A1/de not_active Withdrawn
• 2010
  • 2010-02-03 EP EP10702865A patent/EP2384542B1/de not_active Not-in-force
  • 2010-02-03 JP JP2011549517A patent/JP2012517756A/ja active Pending
  • 2010-02-03 WO PCT/EP2010/051269 patent/WO2010091982A1/de active Application Filing
• 2011
  • 2011-08-02 US US13/196,612 patent/US8547181B2/en not_active Expired - Fee Related

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